关于循环子群数目超过一半的几乎单群

假设G为有限群,记c(G)为群G的循环子群个数,α(G)为群G的循环子群个数与群阶数的比值,即α(G):=c(G)/|G|。本次研究证明了若G为几乎单群,即S ≤ G ≤ Aut(S),这里S为有限非交换单群,则α(G)≥ 1/2当且仅当G≅A₅,S₅,S₆。     

流域分块对汇流参数的影响

选择屯溪、东湾及王快流域为典型流域,挑选合适的目标函数,采用单纯形法率定参数,研究流域分块对新安江模型S_M、C_S、C_I及C_G等参数的影响。结果表明,随着流域分块数增加:降雨资料均化程度减小,S_M呈增大趋势,C_S呈减小趋势,C_I及C_G基本保持不变;洪量、洪峰合格数及确定性系数均呈增大趋势,当子流域面积小于1 000 km²时模拟精度大幅度改善。     

各向异性影响非等温凝固过程的相场法模拟

采用相场法,模拟Ni-Cu二元合金非等温凝固时各向异性系数对晶体生长行为的影响.结果表明,各向异性系数越大,二次枝晶越发达,枝晶生长速度越快.潜热的释放,致使固相区温度比液相的高,而且在二次枝晶生长速度最快的固/液界面处的温度最高.固/液界面温度的升高,使过冷度降低,晶体的生长受到抑制,生长速度出现波动.     

一个构造等能量图族的方法

一个图的能量定义为图的邻接矩阵的特征值的绝对值之和,是一类重要的图指标. 利用矩阵性质给出了一类联并图的谱刻划：正则图G₁,G₂,…,G_n的联并图G［G₁,G₂,…,G_n］的谱是由正则图G₁,G₂,…,G_n的谱（去掉每个正则图的第一个最大特征值）和一个由图G决定的辅助矩阵的特征值组成. 这个刻划能够给出一个构造等能量图的方法. 作为方法的应用,给出一些等能量图的例子.     

Na2Ce4(MoO4)7晶体的生长及磁光性能研究

采用提拉法生长Na₂Ce₄(MoO₄)₇晶体,通过XRD测试证实其为白钨矿结构,空间群为I4₁/a. 测试晶体在400~1600nm波段的透射光谱,其在600~1600nm波段透过率较高,大约77%~79%. 晶体中Ce³⁺稳定存在,退火前后均未发生变价. 不同方向磁化率的测定表明,Na₂Ce₄(MoO₄)₇晶体为顺磁性且存在明显的磁各向异性,其易磁化方向与光轴方向一致. 采用消光法测试晶体在635、 1064nm处的法拉第旋转角,计算得到的费尔德常数分别为：-194.5、 -58.5rad·(m·T)^-1,约为TGG晶体的1.46倍.     

GL2(C)的一些不可约表示

设G=GL₂(C), 并且B是G的标准Borel子群, 并且CG, CB分别是群G和群B的在复数域C上的群代数.对于任意B的特征标θ, 定义G的离散诱导模M(θ) = CG×_CBθ. 证明了当θ是反支配权时,M(θ)是个不可约表示.由此给出了一类GL₂(C)全新的、无限维的不可约表示.     

统一混合变速增长网络中熵与混合比的关系

研究了统一混合变速增长网络(UHVSG)中不同参数下网络的熵特性BGS和S_q,数值模拟计算了指数α、3个混合比dr,gr和fd 4个参数下BGS、S_q熵的变化关系.结果表明BGS和S_q 熵都随着α的增加而升高;BGS随着dr的增加而缓慢减小;fd对熵产生的影响比gr产生的影响更大; S_q随着fd和gr的增加而减少; S_q 受dr的变化影响较小. 相关结论将有助于理解UHVSG模型的演化机制, 为其在实际网络的应用设计提供一定科学依据.     

BaB2O4单晶快速生长时的界面形态与表面台阶形貌

利用微分干涉显微镜和原子力显微镜, 分别研究了快速生长的BaB₂O₄单晶固液界面形状的演化和晶体(0001)显露面上的台阶形貌. 结果显示, 在快速生长条件下, 晶体固液界面会由平坦状向骸晶状界面转变; 而晶体表面台阶的形貌与晶体生长的方向密切相关, 沿着<1010>方向运动的台阶束构成台阶流形貌, 而沿着<0110>方向运动的台阶束则表现为台阶片段的形貌. 通过AFM分别计算了表面上不同方向排列的纳米尺度上台阶的高度, 从而估算了晶体生长构造单元的尺寸, 结果说明在快速生长时溶液过饱和场的极度不均匀性造成的构造单元尺度和台阶聚并行为的各向异性是引起台阶流形貌各向异性的主要原因.     

过冷纯熔体中晶体生长扰动解的可解性条件

在晶体液固界面上考虑动力过冷,对凝固系统控制方程的扰动解进行渐近展开,分别求其零级、一级近似解.推出判别液固平界面稳定性的色散关系,该关系式适合于任意的扰动波长.结果表明,过冷纯熔体中非快速凝固晶体生长的液固界面是不稳定的.     

具强迫项的中立型差分方程的振动性和渐进性

 使用不等式的某些技巧,获得了如下具强迫项的中立型差分方程Δ(y_n+y_n-τ)+Q_nG(y_n-σ)=f_nn∈N的所有解振动或当n→∞时趋于零的充分条件.还获得了如下的中立型差分方程Δ(y_n-y_n-τ)+Q_nG(y_n-σ)=0 n∈N的所有解振动的充分条件.     

Itinerant-electron metamagnetic transition and giant magnetic entropy change in La0.8Ce0.2Fe11.4Si1.6 compound

Iron-based rare-earth intermetallic compounds LaFe13?xSix (1.2≤x≤2.6) and CeFe13?xSix (2.4≤x≤2.6) both have the cubic NaZn13-type structure with Fm3c(Oh6) space-group symmetry[1―3]. Fujita et al. [4] demonstrated that the cubic NaZn13-type LaFe13?xSi     

邻香草醛缩胱氨酸双Schiff碱的合成及其对粟酒裂殖酵母细胞生长代谢的热动力学研究

用摩尔比为2:1的邻香草醛(C_8H_8O_3)与L-胱氨酸(C_6H_(12)N_2O_4S_2)反应,合成了一种新的双Schiff碱化合物--双{2-[(3-巯基丙酸钠)-2-亚胺基-甲基]-6-甲氧基-苯酚}(OVCS)。通过元素分析、红外光谱、核磁共振等手段对其组成和结构进行了表征,确定其化学式为Na_2(C_(22)H_(22)N_2O_8S_2),采用TAM air微量热仪测定了新合成的Schiff碱化合物(OVCS)在305.15 K时对粟酒裂殖酵母细胞作用的产热曲线;根据产热曲线计算了在OVCS作用下,粟酒裂殖酵母细胞生长代谢的最大发热功率p_(max)、速率常数k、传代时间tG、抑制率I和半抑制浓度C_(I,50)等热动力学参数。通过实验可以发现随着OVCS浓度的增加,粟酒裂殖酵母细胞的生长代谢速率常数k、生长代谢的总热效应Q_(total)、最大发热功率p_(max)均减小,抑制率I、达到生长代谢最大功率所需时间t_(max)、传代时间tG均增加等规律,半抑制浓度C_(I,50)为35.99 mg/L(或9.62×10~(-2)mol/L)。实验结果表明,OVCS对粟酒裂殖酵母细胞有抑制作用,且浓度越大,抑制作用越强。     

An investigation on supercooling directional solidification process of Cu-Ni single phase alloy

Supercooling directional solidification (SDS) is put fotward by combination of melt supercooling and conventional solidification by application of supercooling inheritance. On the self-designed SDS equipment, SDS of Cu-Ni alloy was achieved successfully The results are as follows f (i) The primary arm spacing is about 30 μm, the growth of secondary arms are strongly suppressed. The primary arm spacing is nearly the same as LMC method (GL=25 K/mm, V=500 pm/s), the primary stems are straight, fine and completed. with an inclination angle of about 5.8° (ii) A semi-quantitative T-T model is brought fotward to describe the dendrite growth rate V vs. undercooling AT The prediction of T-T model agrees well with experimental results. The formation of fine equiaxed dendrites, transition region and dendrite region can be explained successfully by △T-V-x relation of T-T model.     

Morphologic characteristics and growth interface stability of nano-micron FeS2 whiskers

Micromorphology is further studied on the basis of our previous researches concerned with the nano-micron FeS2 whisker. There are obvious differences in the intensive degree, diameter and micro- morphology among the FeS2 whiskers growing in different stages. From the early to late stage, the intensive degree increases, the diameter decreases, and the surface micro-morphology changes following the regularity： protrusive nodulation → coarse → smooth → flat. According to the theory of crystal growth, the geological setting and processes of whisker formation, we discuss the stability and evolution of crystal growth interface of FeS2 whisker occurring in Gengzhuang gold deposit （Shanxi Province, China）. The results suggest that the negative temperature gradient and the supercooling appear in the early stage of the whisker growth, whereas the positive temperature gradient of reposeful state appears in the late stage. In the whisker growth stage, the component concentration changes through the three stages： severely nonhomogeneous in the early stage, relatively homogeneous in the middle stage, more homogeneous in the late stage. The general changing process of the interfacial state is from unstable to stable. Micromorphology of FeS2 whisker in Gengzhuang is the result of synergism of temperature, component concentration and stability of crystal interface phase in hydrothermal system. The micromorphology not only reflects the physical and chemical characteristics of the hydrothermal system during the whisker growth, but also indicates the stability characteristics of the interface phase and records the changing process of the whisker growth.     

Giant magneto-optical faraday effect of nanometer Fe-In<Subscript>2</Subscript>O<Subscript>3</Subscript> granular films

The giant magneto-optical Faraday effect of nanometer ferromagnetic metal-semiconductor matrix Fe-ln2O3 granular films prepared by the radio frequency sputtering are studied. The result shows that the Faraday rotation angle θF value of the granular film samples with Fe volume fraction x = 35% is of the order of 10^5（°）/cm at room temperature. Temperature dependence of the Faraday rotation angle θF of Fe0.35（In2O3）0.65 granular films shows that θF value below 10 K increases rapidly with the decrease of the temperature, and when T= 4.2 K, θF value is 106（°）/cm. Through the study of the dependence of low field susceptibility on temperature and the hysteresis loops at different temperatures, it has been found that when the temperature decreases to a critical point Tp = 10 K, the transformation of state from ferro-agnetic to spin-glass-like occurs in Fe0.35（In2O3）0.65 granular films. The remarkable increase of the Faraday rotation angle θF value of Fe0.35（In2O3）0.65 granular films below 10 K seems to arise from the sp-d exchange interaction of the granular film samples in the spin-glass-like state.     

Mechanical,electrical, and thermal properties of the directionally solidified Bi-Zn-Al ternary eutectic alloy

A Bi-2.0Zn-0.2Al (wt%) ternary eutectic alloy was prepared using a vacuum melting furnace and a casting furnace. The samples were directionally solidified upwards at a constant growth rate (V = 18.4 μm/s) under different temperature gradients (G = 1.15–3.44 K/mm) and at a constant temperature gradient (G = 2.66 K/mm) under different growth rates (V = 8.3–500 μm/s) in a Bridgman-type directional solidification furnace. The dependence of microstructure parameter (λ) on the solidification parameters (G and V) and that of the microhardness (Hv) on the microstructure and solidification parameters were investigated. The resistivity (ρ) measurements of the studied alloy were performed using the standard four-point-probe method, and the temperature coefficient of resistivity (α) was calculated from the ρ-T curve. The enthalpy (ΔH) and the specific heat (C_p) values were determined by differential scanning calorimetry analysis. In addition, the thermal conductivities of samples, obtained using the Wiedemann-Franz and Smith-Palmer equations, were compared with the experimental results. The results revealed that, the thermal conductivity values obtained using the Wiedemann-Franz and Smith-Palmer equations for the Bi-2.0Zn-0.2Al (wt%) alloy are in the range of 5.2–6.5 W/Km and 15.2–16.4 W/Km, respectively.     

Zr50Cu50金属玻璃形成过程中自由体积与玻璃态转变温度关系的分子动力学模拟

利用分子动力学模拟了Zr50Cu50金属玻璃的形成过程,并获得了不同温度下合金的原子构型.借助金属玻璃中自由体积量等于金属玻璃与对应晶体的体积差理论提出一种自由体积湮没速度法,对Zr50Cu50金属玻璃形成过程中的临界玻璃态转变温度Tc以及热力学玻璃态转变温度Tg进行预测.用该方法确定出的Tc(969.5K)与利用模式耦合理论计算获得的Tc(978.4K)接近;Tg(731K)与利用平均原子体积随温度变化关系曲线确定的Tg(725K)相近.运用自由体积湮没速度法计算的Tc和Tg无需计算各温度下的原子扩散系数,节省了计算时间.     

The formation depth of coesitebearing eclogite, Dabie UHPM zone, China, modified by tectonooriginal additional hydrostatic pressure

The knowledge that hydrostatic pressure is equal to the gravity value of the overlying rocks in studying a dynamic state of certain underground site is argued. It is suggested that the stress field T in the crust is a combination or superposition of total hydrostatic pressure P with differential stress σ , and the total hydrostatic pressure P at any point in the crust comprises two parts: one is spherical stress tensor PG caused by the gravity, and the other is spherical stress tensor Ps caused by tectonic stress; therefore P could not be attributed to the gravity of overlying rocks only. The results obtained by a finite-element simulation indicate that the tectono-original additional hydrostatic pressures Ps decrease gradually from the compressive zone (Pcs) to the shear zone (PSHs) and to the tensile zone (PTs), i. e. PCS>PSHs> PTs in the same depth. On the basis of the above-mentioned research, the method of measurement and calculation of metal logenetic depth corrected by Ps is established, i.e. first tectonic additional hydrostatic pressure Ps is removed from general hydrostatic pressure P to get PG, gravity additional pressure, then accordingly the depth data are measured and calculated. The plastic deformation of garnet in coesite-bearing eclogite, quartz eclogite and garnet amphibo-lite of the ultrahigh-pressure metamorphic (UHPM) complex in the Yingshan County in Dabie Mt. is studied by the transmission electron microscope (TEM). It is shown that the garnets have ductile deformation in the metamorphic condition of eclogite and amphibolite facies. Microstructures of the garnet vary greatly among coesite-bearing eclogite, quartz eclogite and garnet amphibolite. The tectonic principal stress in three-dimensional space and the tectonic additional hydrostatic pressure are reconstructed by differential stress and strain ratio (α) of garnet in minor coesite-bearing eclogite, then the gravity and thickness of overlying rocks are determined. The formation depth of ≥ 32.09-32.106 km of the coesite-bearing eclogite in Yingshan County in the Dabie UHPM zone is obtained from difference PG which comes from P minus Ps, Ps = (σ1 + σ2 + σ3) /3. The value of P is 2.8 GPa resulting from Qz-coes geobarmeter. This result is at all different from other researchers' conclusion that the formation depth of eclogite in Dabie UHPM zone is ≥100 km by the method of weight/ special weight (W/SW). The strong tectionic action makes a great contribution to the formation of e-clogite in the Dabie UHPM zone at so shallow depth of about 32 km, therefore it is thought that attention should be paid to the tectonc-original additional hydrostatic pressure in the study on UHPM zone.     

K_xNa_（1－x）Cl复合基质晶体生长

运用相变动力学和相变热力学的基本原理，分析、讨论复合基质晶体生长的难易程度、生产界面与组分过冷的关系等问题，给出了ＫｘＮａ１－ｘＣｌ复合基质晶体生长的研究结果．     

Mechanical properties of directionally solidified lead-antimony alloys

The Pb-17wt% Sb alloy was directionally solidified under two solidification conditions: with different temperature gradients (G=0.93–3.67 K/mm) at a constant growth rate (V=17.50 μm/s) and with different growth rates (V=8.3–497 μm/s) at a constant temperature gradient (G=3.67 K/mm) in a Bridgman furnace. Microstructure parameters, such as primary dendrite arm spacing (λ₁), secondary dendrite arm spacing (λ₂), and dendrite tip radius (R), were measured. The microhardness (Hv) and ultimate tensile strength (σ) of the directional solidification samples were also measured. The influences of solidification and microstructure parameters on Hv and σ were investigated. The results obtained in this work were compared with similar experimental researches in literatures. It is shown that the Hv and σ values increase with the increase of G and V, but decrease with the increase of λ₁, λ₂, and R.